The AMD K5 was AMD's first in-house x86 processor and was introduced in march 1996. The AMD K5 wasn't a big success at that time because it was delayed and AMD's 90MHz and 100MHz parts were introduced 2 full years later Intel's Pentium at 90MHz and 100MHz.

This is the second generation AMD K5 that is based on the 5k86 core. It has been optimized a bit and should be faster per MHz than the original one. Because of this AMD used the PR number (Performance Rating) to indicate performance. The original AMD K5 PR75, PR90 and PR100 ran at respectively 75MHz... > Read more